This invention contemplates a series device of load-break switch and current-limiting fuse, wherein the switch is to break load currents and small overload currents, i.e. currents not exceeding a small multiple of the rated current of the load-break switch, all fault current of higher magnitude being handled by the current-limiting fuse. In other words, the current-limiting fuse is relieved under such circumstances from interrupting relatively small overload currents. This greatly simplifies the design of the current-limiting fuse as compared to an all purpose current-limiting fuse which must be capable of interrupting the full range of currents, from the smallest overload current to the largest fault current. It has been observed that under the contemplated conditions but a relatively small portion of the pulverulent arcquenching filler of the fuse is converted into a fulgurite. This means that the portion not coverted into a fulgurite represents, at best, an unnecessary safety factor which can readily be dispensed with. The space gained by reducing the volume of arcquenching filler can be used to accommodate a load-break disconnect, or at least a part of its operating mechanism.